Question

lf the length of a seconds pendulum is increased by 2%, then in a day the pendulum

• A. loses 764 s
• B. loses 924 s
• C. loses 236 s
• D. loses 864 s

Answer 1

Answer: (D)

loses 864 s

Answer 2

Time period, T = $2 \pi \sqrt{ \frac{ l }{ g }}$
or $\frac{ \triangle T }{ T } = \frac{ 1}{ 2} \frac{ \triangle l }{ l }$
For ls, $\triangle T = \frac{ 1}{2} \bigg( \frac{ \triangle l }{ l } \bigg) T = \frac{ 1}{ 2} \times 0.02 \times T = 0.01 T = 0.01 s$
For a day, $\triangle T = 24 \times 60 \times 60 \times 0.01 = 864$s